The present invention relates to an automatic analyzer having a function of detecting the remaining quantity of a liquid being used (reagent, diluent liquid, cleaning liquid, or the like).
In an automatic analyzer, liquids such as reagents and cleaning liquids are used. If these liquids are used up during measurement, not only can the measurement not be continued in such a state, but also the results of the measurement cannot obtained from the specimens in measured or the process of reaction. Generally, a spare liquid tank is incorporated in the analyzer so that the effect may not appear immediately if an external liquid tank becomes empty.
In some automatic analyzers, it takes a long time (more than scores of minutes) from sampling of the liquid specimen until the result of the measurement is produced. For example, it takes a long time in the reaction process between the liquid specimen and a reagent, or in the measurement process of the reaction liquid. The antigen-antibody reaction is one such example.
When treatment of one specimen requires a long time, treating processes of plural specimens are overlapped to improve processing capacity.
In the case of such an overlapped treatment, if the liquid is used up on the way, the apparatus stops. If refilling is attempted with a fresh liquid while stopped, bubbles are formed, which may cause a measuring error. Besides, if it is required to perform a reaction process in a specific condition, the reaction time varies and a correct result is not obtained. In particular, in the case of an immunity apparatus, the reaction process is conducted in severe conditions in specific circumstances. Accordingly, if one runs out of the liquid in the midst of the operation, all specimens in the treatment process are wasted, and the operation must be started from the beginning, which means an increase in the running cost and loss of time.
Hitherto, the operator checked the remaining quantity of reagents and other liquid before starting a measurement, and replaced the liquid with new liquid if it was estimated to run short in the midst of the operation. Of course, the liquid may be replenished during measurement, but bubbles may be formed and a measuring error may result.
It is, however, bothersome to check the remaining liquid quantity, and problems were often caused when forgetting to check or mispredicting the remainder.